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Thermal Cameras Did Not Increase Overall Aerial Culling Rates in a Chital Control Program

Three wild chital in Bandipur National Park
Conservation · Management

A trial during a feral-deer control program near Collinsville in Queensland, Australia found that adding thermal imaging did not significantly increase the overall rate at which animals were removed from helicopters. The program targeted chital (Axis axis) and rusa deer (Cervus timorensis), with the study area containing a large contiguous chital population; feral pigs (Sus scrofa) and wild dogs (Canis familiaris) were also culled opportunistically.

The study, published on 13 April 2026, analysed 20 aerial shooting flights carried out in July and August 2024 across a 1,996-square-kilometre area of 12 cattle properties. Fourteen runs used a thermal-camera operator and six relied on conventional visual detection.

Thermal imagery found many animal groups

The camera worked under a range of temperatures and canopy conditions, but it was considered usable for the full duration of only eight of the 14 thermal-assisted flights. On the other six, its use was limited for parts of the flight by ambient conditions or because high animal densities made visual detection sufficient. During the thermal-assisted runs for which the initial detection method was recorded, thermal imagery accounted for 65% of detections across the animal groups analysed. For deer groups specifically, 67.4% of recorded initial detections were made with the thermal camera rather than by unaided visual observation. The authors caution that this does not show that those groups would necessarily have remained undetected without the camera.

Across all 20 flights, 1,881 animals were removed: 1,365 deer, 508 feral pigs and eight wild dogs. The authors note that the combined cull data were dominated by chital, although the deer total also included rusa deer.

Overall removal rates were not significantly higher

Despite the additional detections, the researchers found no significant overall increase in the number of animals removed per hour or per kilometre flown when thermal assistance was used. Search and pursuit times also showed no consistent overall improvement.

Animal density appears to have been important. Parts of the Collinsville area had previously held very high deer densities, reaching up to 48.3 deer per square kilometre. At such densities, animals were already relatively easy to find visually and the operation could be limited more by the time needed to pursue and remove animals than by the search itself.

Benefits may be greater when animals become harder to find

The limited low-density comparisons pointed in that direction. In both matched low-density deer areas, thermal-assisted runs removed more animals per hour than conventional runs: 27.9 versus 23.7 in one area and 60.3 versus 13.8 in the other. Thermal-assisted runs also found proportionally more very small deer groups: 45% of deer groups contained one or two animals, compared with 26.3% on conventional runs. The authors stress that these advantages were not consistent across the full trial.

The thermal observer increased the hourly cost of the operation by about 20.5%, and this extra cost was not offset by a higher overall culling rate during the trial. The authors nevertheless conclude that thermal imagery can still be useful, particularly when animal densities are lower, animals occur in smaller groups or dense vegetation makes visual detection difficult.

Sources and image credit

  1. Gentle, M. N., Sydenham, A., Fuller, B., & Pople, A. R. (2026). An assessment of thermal detection in aerial culling of feral deer and pigs in northern Australia. Wildlife Research, 53(4), WR25195. https://doi.org/10.1071/WR25195Primary peer-reviewed article published 13 April 2026. Twenty aerial culling flights near Collinsville compared 14 thermal-assisted runs with six conventional runs. Thermal imagery made 67.4% of deer-group initial detections with known detection method during assisted runs, but did not significantly increase overall animals removed per hour or kilometre; 1,881 animals were removed in total.

Image: Anvesh Sharma — three wild chital in Bandipur National Park, India, photographed 14 April 2017; Wikimedia Commons; representative species image, not animals from the Queensland study · CC BY-SA 4.0 · Source

About this content: This story was produced with AI assistance within an editorial workflow developed by Wildlife Vagabond. Editorial responsibility remains with Wildlife Vagabond.How AI is used

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Chital Axis axis Explore species Wild Boar Sus scrofa Explore species

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